Steam boiler with superheater and reheater



Oct. 18, 1932.

H. J. KERR STEAM BOILER WITH SUPERHEATER AND RBI-{EATER Filed Nbv. 21,1929 Fi gr 1 L l L .4 2 6 I/T, ,2, 0 0 0 0 o M O O O O O 0 o 0 o O 2) O.20 Y; 1 z 10 v 1 V.

1 i j v INVENTORV Patented Oct. 18, 19 32 UNITED STATES PATENT; OFFICEHOWARD J. KERR, OF WESTFIELD, NEW JERSEY, ASSIGNOR TO THE BABCOCK 82;WILOOX COMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEYSTEAM BOILER WITH SUPERHEATER AND REHEATER Application filed November21-, 1929. Serial No. 408,702.

This invention relates to a steam boiler having the steam generatingsurfaces, superheater surfaces and reheater surfaces so arranged thatthe gases for the reheater are i sufliciently hot. The superheater mayalso 0 companying drawing in which be heated in part by radiant heatfrom the furnace.

The invention will be understood from the description in connection withthe "acig. 1 is a vertical section through an illustrative embodiment ofthe invention; Fig. 2 is a section along the line 22 of Fig. 1; and Fig.3 is a front view of some of the headers.

In the drawing, reference character 1 indicates the upper portion of aboiler furnace above which a boiler of the Babcock & Wilcox type islocated. The boiler comprises the usual steam and water drum 2 connectedby nipples 3 to downtake headers 4:. A bank of inclined tubes 5 connectsthe downtake headers 4 to uptake headers 6. The bank of inclined tubes 5differs from the usual bank of inclined tubes in boilers of this type byhaving alternate rows of tubes omitted for some distance from the lowerportion of the bank as most clearly shown in Fig. 3. In the illustrativeembodiment of the invention, the second, fourth and sixth rows of tubesfrom the bottom are omitted, thus leaving a smaller number of tubesspaced farther apart, which-will act as a slag screen and will alsopermit a certain amount of radiant heat from the furnace to pass throughthe bank of tubes.

The upper ends of the uptake headers 6 are connected by rows ofcirculating tubes-7 to'the steam and water drum 2. Straps 8 fromsupports 9 extend around the ends of the tubes 7 where they areconnectedto the headers 6 for supporting the same. These ends of the tubes 7 areprotected from direct contact with hot ases from the furnace by an arch10 of re ractory material that extends from the upper portions of theheaders 6 to the lower end of the outer wall of the gas flue 11. Thearch 10 may be supported by a support 10'.

a A tube 12 extends from the steam space of the steam and water drum 2to the inlet thereon.

header 13 of the superheater. The header 13 is supported from the bankof tubes 5 by means of supports 14. A bafie-15 extends from the headers4 along the upper side of the upper row of tubes, 5 and thence acrossthe superheater tubes 16 in front of the header 13. The superheatertubes 16 extend from the inlet header 13, to the outlet header 17. Thesetubes are inclined at a greater angle than the tubes 5 and are bent sothat they can expand and contract. The

tubes in the bank nearest the gas stream are staggered and spacedfarther apart than the others, as shown in Fig. 2, thereby assistingdistribution of hot gases within the bank of superheater tubes. A bafiie18 extends along the upper side of the superheater tubes 16 and asliding gas seal 19 is provided between the superheater header 17 andthe lower end of one wall 20 of the flue 11, which extends across thetubes 7 about midway between the ends of these tubes.

The upper end of the flue 11 is connected to the upper end of thedown-flue 21 in which the reheater is located. 7

The reheater may be used for reheating steam between stages of aturbine. It comprises an inlet header 22 located along one side of theflue 21 and connected by rows of serpentine tubes 23 to the header 24:.The header 24: is connected by rows of U-tubes 25 to the outlet header26. The U-tubes 25 extend beyond the wall 20 and are supported Crosssupports 27 are provided for the tubes 23 and 25 to keep them properlyspaced. One of the rows of cross supports 27 rests upon brackets 28 thatare supported by the su ports 29, which also support the wall 20. crosssupport 30 is also indicated for the other wall of the flue 11.

By having a small number of inclined tubes 5, the gases which pass fromthe furnace 1 across these tubes will retain a considerable amount oftheir heat. The superheater tubes 16 are not burned out as the gases donot pass directly across these tubes, but only the gases along one sideof the gas path contact with these tubes and move along the samesubstantially parallel to them. The radiant heat from the furnace thatreaches 7 primary superheater,

the superheater tubes 16 gives a more uniform superheat at variousratings. Also, the objection of the superheater giving higher superheatsat higher loads is avo1ded, because of the fact that most of the gasesare by-passed without contacting directly with the tubes of thissuperheater.

After the gases cross the tubes 5 and most of them have by-passed thesuperheater, they cross the tubes 7 and flow upwardly in the flue 11,thence downwardly in the flue 21 across the reheater tubes 23 and 25 andagain across the tubes 7 at another place. The gases then pass betweenthe baflie 18 and drum 2 and out between the nipples 3 into the outlet31 of the stack.

In the boiler illustrated in this application,

the steam generating surface 1s small compared to the reheater orsecondary superheater surface. Therefore, the primary superheater islocated at one side of the pat for the gases after they have passedacross steam generating surface so that the primary superheater tubeswill not be contacted by all of the ases that pass through the boilersetting. he quantity of steam that is generated in the boiler and passesthrough the primary superheater is comparatively small compared to thequantity of steam that passes through the reheater so that the degree ofsuperheat in the primary superheater would be too great if all of thegases were to contact with the primary superheater. By this invention aproper balance can be maintained between the amount of heat absorbed bythe steam generating surfaces of the boiler, the

and the reheater, re-

spectively.

I claim:

1. In a boiler, a bank of inclined steam generating tubes, a superheaterlocated along one side of the gas path beyond said bank of tubes havingits tubes inclined at a greater heater tubes adjacent the gas'path beingspaced apart farther than those remote from said gas path. I

2. In a power steam installation, a steam boiler including a furnace, abank of inclined steam generating tubes above said furnace, the ma]or1tyof said tubes being arranged in 'rows providing straight unobstructedgas lanes permitting the transmission of radiant heat from said furnace,a flue directing heating gases from said furnace between said rows oftubes, a steam retubes being more widely spaced on the side of thesuperheater nearest the center of the flue, said superheater beingarranged to absorb heat both by radiation and convection, whereby thedegree of superheat is not unduly increased at high ratings.

3. In a boiler, a bank of inclined steam generating tubes, and asuperheater located out of the main path of the gases beyond said bankof tubes, the superheater tubes adjacent the gas path being spaced apartfarther than those remote from said path.

4. In a boiler, a furnace, a gas pass leading from the furnace, a bankof inclined steam generating tubes of relatively low heat absorptivecapacity extending across the gas pass above the furnace, the tubes ofsaid bank being arranged to permit the transmission of radiant heat fromthe furnace to a portion of said gas pass above said bank, a bank offluid heating tubes in said gas pass subsequent to said steam generatingtube bank with respect to gas flow, said gas pass havin a wall sectionabove said steam generating bank and ,in position to absorb heatradiantly transmitted from the furnace, and a superheater having tubesextending along and cooling said wall section and absorbing heat both byradiation and convection.

HOWARD J. KERR,

' angle than the tubes of said bank, the supera steam superheatercomprising

